FORM2
THE PATENTS ACT, 1970
(39 of 1970)
&
The Patents Rules, 2003
COMPLETE SPECIFICATION
(See section 10; rule 13)
1. Title of the invention - AN IMPROVED MECHANISM TO SUPPORT
THE STRIP DURING PARTING OPERATION IN A PRESS TOOL
2. Applicant(s)
(a) NAME : LARSEN & TOUBRO LIMITED
(b) NATIONALITY : An Indian Company
(c) ADDRESS : L & T House, Ballard Estate, Mumbai 400 001,
State of Maharashtra, India
3. PREAMBLE TO THE DESCRIPTION
The following specification particularly describes the invention and the manner in which it is to be performed:

FIELD OF THE INVENTION
The present invention relates to an improved mechanism to support a strip during parting operation in a press tool. More particularly, the present invention relates to an improved mechanism in a press tool for generating accurate components separated from said strip/coil by giving support to the strip during parting operation.
BACKGROUND OF THE INVENTION
Press tools are used for processing coils / strip in Progressive punching, cutting operations. In parting operation, component is separated from the strip/coil by a parting punch. Here we provide relief angle to the Die plate and Base plate for the ease of component falling. The strip/coil is unsupported at the time of parting. Due to this, a taper edge is generated on component at the time of parting operation. This problem is observed particularly when the strip / coil thickness is greater than or equal to 2mm. Because of this, component / stamping accuracy gets affected. Also, the component length increases beyond the specified limit, leading to rejections of the component. The length of component / stamping is inconsistent. Thus it is essential to support the strip/coil at the time when parting operation takes place. This mechanism supports the strip/coil from outside the feeding region and comes into action just before parting operation takes place and supports the strip with the help of spring actuated slider cam mechanism. This mechanism eliminates / minimizes taper edge on parted edge of component within the specified limit of component tolerance without disturbing the feeding of strip and fall of component.
The manufacturing process for sheet metal component or stamping is by processing a sheet metal coil or strip in a press tool. Many times the nominal width of coil or strip is equal to maximum width of stamping to reduce the generation of scrap. The stampings have circular & non circular boles placed in such a way product

design) that the distance between piercing hole and the outer edge (which gets parted off) of component is very important & it is a critical to quality size or dimension of component. The parting punch profile is the same as the component profile at the ends. The sheet metal strip or coil may be of ferrous or non ferrous materials.
Press working is one of the major processing techniques for converting sheet metal into sheet metal parts of different shapes. The sheet metal parts are required for different applications such as Electrical / electronic products, Automobiles, Watches etc. The sheet metal is punched between two parts called punch & die. The die profile is the female profile intentionally kept bigger than the punch profile by a uniform gap called cutting clearance.
Press tool mainly consists of two halves, namely fixed bottom half and a moving top half. The fixed bottom half is secured to the stationary bolster plate of mechanical press. It comprises arrangement to guide the strip/coil, die cavities, guide pillars for alignment of both halves etc. The top moving half is clamped to the moving ram of the mechanical press & it comprises a no. of circular & non circular cutting & non cutting elements called punches. The punches move up & down along with the moving ram of the mechanical press & they are guided in cavities made in a plate called Stripper. During downward movement, the punches penetrate the sheet metal & enter the die cavity thus pushing the sheet metal scrap displaced by the cutting punch into the lower half of the tool. One downward & return upward movement of the top half of press tool is called as stroke of press tool. Surrounding metal clings to the body of cutting punches during downward stroke. The same is stripped off by the stripper plate during upward stroke of the punches.
Press tool may be of multi station type (progressive) or single station type. In a multi station tool, the strip moves from one end of strip guides to the other end. It moves progressively by a fixed distance called pitch after every stroke of the mechanical

press. At each stage of movement of strip, different punching operations are carried out on strip / coil leading to completion of stamping profile in last stage.
The gap in the strip guides is always kept slightly bigger than the maximum size of strip / coil width for ease of strip/coil feeding. At the time of parting, it is not possible to avoid generation of taper edge on the component. There is always a chance of tilting the strip due to non availability of support to the strip during parting operation. This will not allow the maintenance of the width & length of component accurately & lead to rejection of stampings by Quality control department.
The drawbacks of the above mentioned prior art is that the component was separated from the coil / strip by parting operation without having support to the strip at the time of parting. The tapered edge is generated on the stamping at the time of parting operation. However, this resulted in loss of component accuracy in the form of component length at the end. There was no consistency in the straight edge of component & holes dimensions with respect to parting edge of component as prescribed in the component design.
Thus there is a need to provide an improved mechanism to support a strip during parting operation in the press tool such that the product design requirement of straight cut edge of a component is achieved, the construction takes care of avoiding taper edge of coil / strip at the parting operation, the construction ensures free fall of the stamping / component after parting operation and ease of assembly and maintenance.
The present inventors have developed a spring loaded Slider Cam Mechanism that is used for achieving the above requirement of supporting the strip at the time of parting operation and getting component accuracy as prescribed in the component design.

OBJECTS OF THE INVENTION
An object of the present invention is to overcome the problems/disadvantages of the prior art.
Another object of the present invention is to provide an improved mechanism to support a strip/coil during parting operation in the press tool.
Yet another object of the present invention is to provide an improved mechanism such that the component from strip/coil is achieved with straight cut edge.
Yet another object of the present invention is to provide an improved mechanism to ensure free fall of the stamping / component after parting operation and Ease of assembly, maintenance.
Yet another object of the present invention is to provide an improved mechanism adapted to takes care of the variation in component length and avoiding taper edge of coil / strip at the parting operation.
SUMMARY OF THE INVENTION
According to one aspect of the invention there is provided an improved mechanism to support a strip/coil during parting operation in a press tool, said mechanism comprising :
(a) fixed bottom half/block;
(b) movable top half/block;
(c) plurality of screws/dowels;
(d) spring means ;

(e) punch means operatively associated with said spring means comprising a top side and a bottom side , said top side clamped with said movable top half with said screws/dowels ;
(f) slide block operatively associated with said punch means being mounted on the fixed bottom block with said screws/dowels, said slide block being provided with predetermined slot substantially at its center adapted to engage said punch means , such that said spring means gets compressed;
said slide block is provided with a threaded hole substantially on its side face to assemble spring means with screw;
(g) sliding support means operatively associated with said spring means
having a substantially L-shaped profile comprises of top surface, bottom
surface and vertical edge having a predetermined provision/hole for
engagement of said punch means and said sliding support means being
guided in the slot provided in slide block ;
said bottom surface being embedded on said fixed bottom half,
said vertical edge having a substantially tapered surface adapted for clear stamping during free fall;
said top surface having a substantially flat surface adapted to ensure smooth contact with bottom surface of the strip/coil during parting operation and;
(h) support plate means having substantially a rectangular cross-section assembled with said support means with screws/dowels ,said support plate means having a predetermined provision/hole for movement of said punch means adapted to support movement of the sliding support means

such that during downward stroke of said punch means , the spring means is compressed such that the sliding support means moves forward on the slot provided on said slide means and substantially below the strip/coil edge adapted to support the strip/coil and during upward stroke of said punch means , the spring means being pre-compressed so that the sliding means moves backward with the components on the sliding support means.
DETAILED DESCRIPTION OF THE INVENTION
According to one of the embodiment of the present invention there is provided an improved mechanism to support a strip/coil during parting operation in a press tool comprising fixed bottom half/block; movable top half/block, plurality of screws/dowels; spring means ; punch means operatively associated with the spring means having a top side and a bottom side , the top side clamped with the movable top half with screws/dowels; slide block operatively associated with the punch means being mounted on the fixed bottom block with screws/dowels, said slide block being provided with predetermined slot substantially at its center adapted to engage said punch means , such that said spring means gets compressed, the slide block is provided with a threaded hole substantially on its side face to assemble spring means with screw; sliding support means operatively associated with the spring means having a substantially L-shaped profile comprises of top surface, bottom surface and vertical edge having a predetermined provision/hole for engagement of the punch means and the sliding support means being guided in the slot provided in slide block ,the bottom surface being embedded on said fixed bottom half ,the vertical edge having a substantially tapered surface adapted for clear stamping during free fall and the top surface having a substantially flat surface adapted to ensure smooth contact with bottom surface of the strip/coil during parting operation and ; support plate

means having substantially a rectangular cross-section assembled with said support means with screws/dowels ,the support plate means having a predetermined provision/hole for movement of the punch means adapted to support movement of the sliding support means .
The punch means is cylindrical in shape with said bottom side having substantially bullet shaped tip with tapered angle. The bottom side of the punch means is substantially bullet shaped tip having a predetermined tapered angle.
The slide block has a substantially rectangular profile with its height equal to the top block thickness. The slot means of slide block is adapted to guide the sliding support means. The sliding support means is provided with a hole on its vertical side to accommodate screw/shoulder screw so as to fix the spring. The sliding support means comprises of entry chamfer to facilitate smooth feeding of strip. The sliding support means has width equal to slot in slide block. The support plate means having the length and with substantially equal to the slide block.
During downward stroke of said punch means, the spring means gets compressed such that the sliding support means moves forward on the slot provided on the slide means and further substantially below the strip/coil edge to support the strip/coil. During upward stroke of said punch means, the spring means being pre-compressed so that the sliding means moves backward with the components on the sliding support means.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
Figure 1 illustrates sectional view press tool assembly.
Figure 2 illustrates bottom half top view showing the parting operation and location for strip /coil supporting mechanism.

Figure 3 illustrates strip layout showing parting operation and location for strip / coil supporting mechanism.
Figure 4 illustrates enlarged sectional view.
Figure 5 illustrates enlarged top view of bottom half.
Figure 6 illustrates a slide block.
Figure 7 illustrates a cam.
Figure 8 illustrates a support plate.
Figure 9 illustrates a sliding support.
The invention is now described in details with reference to the accompanying figures. . It is to be understood that some components which are generally present in a press tool assembly are not described in details in the present embodiment as it will be quite evident and understood by a person skilled in the art from the figures and descriptions provided in the foregoing description.
DETAILED DESCRIPTION OF THE ACCOMPANYING DRAWINGS
The coil/strip width supports called Sliding Supports (4) are 'L' shaped objects as shown (Figure J and 2) in the design. They are guided in the slot provided in the Slide Block (1) which is screwed & doweled with the Base Plate (8). A round Cam (2) held in the Top Plate (9) of the top half of press tool, engages with the hole in 'L' shaped Sliding Support (4). The cam (2) is fitted in the top plate (9) and held in position by a socket head cap screw.
The subassembly of Sliding support (4) comprises Screw Sleeve (6), Spring (7) and Washer (10) and it is held by Shoulder Screw (5) with the Slide Block (1). Initially, the spring (7) is in pre compressed state. When the Cam (2) taper surface engages

with the hole of Slide Block (1) during downward stroke of press tool, this spring (7) gets compressed further and the Sliding Support (4) moves forward below the strip edge to support the strip. The Cam (2) is designed in such a way that the 'Sliding supports (4) are below the strip before parting operation. As soon as parting operation takes place, the component temporarily lies on the sliding support (4). As soon as the upward stroke starts, the cam (2) disengages from the sliding supports (4) and the supports move away from strip due to pre compressed load of springs (7). As soon as the supports move away, the component falls down freely. The spring (7) is selected based on the movement required by the Sliding Support (4) to give support to the strip during parting operation. Spring (7) is assembled with Screw Sleeve (6) and washer (10).
Details
The assembly consists of
- (1) SLIDE BLOCK
- (2) CAM
- (3) SUPPORT PLATE
- (4) SLIDING SUPPORT
- (5) SHOULDER SCREW
- (6) SCREW SLEEVE
- (7) SPRING
- (8) BASE PLATE
- (9) TOP PLATE
- (10) WASHER
- (11) SCREW
Figure 6 discloses Slide Block (1) is hardened rectangular steel block, mounted on Base Plate (8) with screws and dowels. This slide block is having one rectangular slot

to guide the Sliding Support (4) on top of its face. The threaded hole is provided on its side face to assemble the spring mechanism with the help of shoulder screw (5).
The sliding support(4) slides on the slot provided as shown with the engagement of cam (2) during downward stroke of the press tool. The clear hole is provided for movement of cam(2).
Figure 7 discloses the cam (2) is cylindrical in shape with a bullet shaped tip at the bottom side. The taper angle of the bullet is kept in such a way to insure ease of engagement with the Sliding Support(4). This is fitted in the Top Plate(9). An extra threading is provided to hold it in the Top Plate (9) by a socket head cap screw. The diameter of the Cam (2) should be big enough to avoid deflection in vertical plane during engagement with sliding support(4).
Working: The Cam (2) is mounted on the moving half of the Press tool. The Cam (2) is held and precisely guided in the Top Plate (9). During downward stroke of the Press tool, the bullet shape at the bottom end of the cam (2) engages with the hole in the Sliding Support(4) . This pushes the Sliding Support (4) forward towards the Strip / coil. The distance between the Flat ends of Sliding Supports (4) is decided based on the maximum width of coil in Tool assembly.
The movement is stopped when the front portion of the Sliding Support (4) moves below the strip from both sides. The height of Cams (2) is kept such that they engage with Sliding Support (4) first and position them in forward most position before parting operation starts. Further downward movement of Cam (2) holds the Sliding Support (4) in position and gives rigid support to the strip/coil before and during parting operation. The stamping separated from strip / coil continues to lie on sliding support during downward movement of Cam (2) after parting operation.
During the upward stroke of the tool, Cam (2) starts moving up and disengages from the Sliding Support (4). At the completion of upward stroke, the Sliding supports (4)

move back to the initial position due to pre compression of spring (7). As a result the component / stamping falls down freely and clears the path for strip feeding.
Figure 8 discloses the Support Plate(3) is rectangular in cross-section having clear hole for Cam (2) movement. The length and width of support plate (3) is kept equal to Slide Block (1). This Support Plate (3) is assembled to the Sliding support block (4) with screws and dowels. The subassembly of the two items forms a rectangular cavity to guide and support movement of Sliding supports (4) during downward stroke.
Figure 9 discloses the Sliding Support (4) is 'L' shaped plate with a provision for engagement of round cam (2) and is well guided in the slot provided in the Slide Block (1) which is screwed and doweled with the Base Plate (8). The top surface of sliding support (4) is flat. This ensures smooth contact with bottom surface of the strip/coil during parting operation. The hole in the sliding support (4) engages with the cam (2) guided and mounted in the Top Plate (9) on the Moving half. The entry taper provided on the top surface of the Sliding support (4) helps in Cam engagement. The taper surface on leading vertical edge keeps itself clear of stamping during free fall. The entry chamfer facilitates smooth feeding of strip. The movement of the sliding supports (4) takes place by the spring compression induced by Cam engagement. A clear hole is provided on the vertical surface of sliding support as shown to accommodate the shoulder screw.
Advantages:
1. Product design requirement of straight cut edge of a component is achieved.
2. The construction takes care of avoiding taper edge of coil / strip at the parting operation.
3. The construction takes care of the variation in component length.
4. The construction ensures free fall of the stamping / component after parting operation.

5. Ease of assembly & maintenance.
The invention has been described in a preferred form only and many variations may be made in the invention which will still be comprised within its spirit. The invention is not limited to the details cited above. The structure thus conceived is susceptible of numerous modifications and variations, all the details may furthermore be replaced with elements having technical equivalence. In practice the materials and dimensions may be any according to the requirements, which will still be comprised within its true spirit.

WE CLAIM
1. An improved mechanism to support a strip/coil during parting operation in a press tool, said mechanism comprising :
(a) fixed bottom half/block;
(b) movable top half/block;
(c) plurality of screws/dowels;
(d) spring means ;
(e) punch means operatively associated with said spring means comprising a top side and a bottom side , said top side clamped with said movable top half with said screws/dowels ;
(f) slide block operatively associated with said punch means being mounted on the fixed bottom block with said screws/dowels, said slide block being provided with predetermined slot substantially at its center adapted to engage said punch means , such that said spring means gets compressed;
said slide block is provided with a threaded hole substantially on its side face to assemble spring means with screw;
(g) sliding support means operatively associated with said spring means
having a substantially L-shaped profile comprises of top surface, bottom
surface and vertical edge having a predetermined provision/hole for
engagement of said punch means and said sliding support means being
guided in the slot provided in slide block ;
said bottom surface being embedded on said fixed bottom half,

said vertical edge having a substantially tapered surface adapted for clear stamping during free fall;
said top surface having a substantially flat surface adapted to ensure smooth contact with bottom surface of the strip/coil during parting operation and ;
(h) support plate means having substantially a rectangular cross-section assembled with said support means with screws/dowels ,said support plate means having a predetermined provision/hole for movement of said punch means adapted to support movement of the sliding support means
such that during downward stroke of said punch means , the spring means is compressed such that the sliding support means moves forward on the slot provided on said slide means and substantially below the strip/coif edge adapted to support the strip/coil and during upward stroke of said punch means , the spring means being pre-compressed so that the sliding means moves backward with the components on the sliding support means.
2. Mechanism as claimed in claim 1 wherein said punch means is cylindrical in shape.
3. Mechanism as claimed in claim 1 wherein said bottom side of the punch means is substantially bullet shaped tip having a predetermined tapered angle.
4. Mechanism as claimed in claim 1 wherein said slide block having a substantially rectangular profile with its height equal to said top block thickness.
5. Mechanism as claimed in claim 1 wherein said slot means of slide block is adapted to guide the sliding support means.

6. Mechanism as claimed in claim 1 wherein said sliding support means is provided with a hole on its vertical side to accommodate screw to fix said spring.
7. Mechanism as claimed in claim 1 wherein said sliding support means comprises of entry chamfer adapted to facilitate smooth feeding of strip.
8. Mechanism as claimed in claim I wherein said sliding support means has width equal to slot in slide block.
9. Mechanism as claimed in claim 1 wherein said support plate means having the length and with substantially equal to said slide block.
10. An improved mechanism to support a strip/coil during parting operation in the press tool, as herein substantially described and illustrated with the accompanying drawings.